Muffler construction



Sept. 29, 1936. R. J. M KENZIE ET AL 2,055,661

MUFFLER CONSTRUCTION Original Filed Dec. 8, 1934 Patented Sept. 29, 1936 UNITED STATES PATENT OFFICE MUFFLER CONSTRUCTION pany, Bufialo, N. Y.

Original application December 8, 1934, Serial No.

Divided and this application November 30, 1935, Serial No. 52,387

7 Claims. (Cl. 181-41) This invention relates to improvements in mufliers or silencers oi the kind which may be used, for example, at the exhaust or intake of an internal combustion engine. More particularly this invention relates to improvements in sound conducting passages or tuning tubes for use in connection with such muiilers or silencers. This application is a division of our pending application Ser. No. 756,638 filed Dec. 8, 1934.

It has been found that in the construction of mufilers or silencers, certain sound waves or noises can best be eliminated by passing the sound waves into a chamber which is connected with another chamber by means of one or more relatively small tubes of greater length than diameter. Such tuning tubes have heretofore been generally made of tubing welded to a baiiie separating the two chambers to be connected by the tubing, and this construction, consequently, involved considerable expense.

An object of this invention is to provide mufflers with sound conducting passages or tuning tubes of improved and simplified construction. Another object of the invention is to provide a mufiler with passages or tubes made entirely of sheet metal and secured to the muiiler by inexpensive means. Another object of this invention is to provide a sound conducting passage or tuning tube made of fiat sheet metal formed into tubular shape and having at the ends of the tube tabs or extensions which may be welded to a part of the muiiler for holding the tuning tube in place and at the same time holding the metal of the tube in tubular form. Other objects of the invention will appear from the following description and claims.

In the accompanying drawing:

Fig. l is a fragmentary longitudinal, sectional elevation of a muffler embodying this invention.

Fig. 2 is a transverse section thereof on line 2-2, Fig. 1.

Fig. 3 is a fragmentary transverse sectional view thereof on line 3-3, Fig. 1, and on an enlarged scale.

Fig. 4 is a plan view of a metal blank from which a tuning tube of the muffler is formed.

l5 represents the outer shell and IS an inner shell of a mufller and I1 and 18 are the end heads or baflles of the muffler which extend inwardly from the outer shell at the ends thereof and which, in the construction shown, are provided with tubular extensions or parts for the inlet and discharge of exhaust gases into and out of the inner shell or conduit IS. The muflier shown also is provided with intermediate heads I9, 20 and 2| extending from the outer shell to the inner shell of the muiiler and forming between them resonator or sound absorbing chambers 22 and 23 separated by the head or baflie 2|. The chamber 23 may receive sound waves from any suitable part of the muiiler, for example, from the inner conduit or shell 16 through openings or apertures 24 therein and the other chamber 22 preferably has no direct communication with the interior of the inner shell or conduit IS. The muiiier construction thus far described is herein illustrated merely for the purpose of showing how our invention may be applied to a muilier and does not constitute a part of this invention, since it will be readily understood that the tuning tubes comprising this invention may be used in connection with any two sound attenuating or resonator chambers, wherever such chambers may be formed in a muflier.

In order to produce certain silencing eifects, it is desirable under certain conditions to connect the chamber 23 with the chamber 22 by means of sound conducting tubes of materially greater length than diameter to produce a bottle neck resonator chamber. For this purpose, in accordance with this invention, we provide a suitable aperture in the baille 2| and through the aperture extends a sound conducting or tuning tube embodying this invention. A plurality of apertures, each provided with a tube of this kind may be provided. These tuning tubes are formed or flat sheet metal, each bent into the form of a tube 25 open at both ends and having the edges of the metal sheet adjacent to the inner shell in the form of a suitable joint which may be either in the form of a butt joint or which may be formed by overlapping the two longitudinal edges, or which may be in the form of a seamed joint, an overlapping joint being shown in the construction illustrated.

The tubes 25 are assembled in a muiiier by inserting the same through the perforations in the baflies and are secured in place by tabs or parts 21 suitably connected with the tubes and secured to an adjacent part of a muflier, such, for example, as a shell. Preferably these tabs are formed integral with the tubes and may be in the form of extensions projecting beyond the ends of the tubes. For example, the sheet metal, prior to being formed into a tube, may have at the corners thereof, tabs or projecting parts 21 which extend lengthwise beyond the ends of the body portion of the tube and which, after the metal is bent into tubular form, are bent toward an adiacent portion of the mufller to which these tabs or projections may be secured. In the particular construction shown, these tabs or projections are bent to extend toward the inner conduit or shell I6 and are spot welded or otherwise suitably secured to the inner conduit or shell. It will be noted that when the tabs or extensions 21 are bent away from the axis of the tubular part 25, they will diverge from each other because of the fact that they are connected with the tubular part 25 at diiferent portions of its periphery. The outer ends 28 of these tabs or extensions 21 may again be bent into any desired shape to facilitate the attaching of the same to another part of the muiller. When constructed in the manner described, the tabs, after they are secured to an adjacent part of the muiiler, serve not only to securely hold a tube in correct position on a muflier, but also to hold the edge portions of the tube which form the longitudinal joint in correct relation to each other and thus to hold the tuning tubes in correct tubular form.

The construction described results in a tuning tube which is made entirely of fiat sheet metal and which has a longitudinal joint which need not be welded or otherwise fastened. These tubes are, consequently, inexpensive to produce and by providing tabs or extensions for connecting the tubes to an adjacent part of a muiller. the cost of securing the tubes in place is greatly reduced since the tabs may be spot welded to the adjacent parts of the mufllers.

We claim as our invention:

1. A muiiier including shells arranged one within the other and spaced apart, a transverse annular bailie extending between said shells and having an aperture, and a sound conducting tube arranged in said aperture and having projections extending laterally therefrom at opposite sides of said baflle and secured to one of said shells for holding said tube in correct relation to said baffie.

2. A mufiier including shells arranged one within the other and spaced apart, a transverse annular baflie extending between said shells and having an aperture, and a sheet metal member having a portion thereof formed into a tube arranged in said aperture and having portions projecting beyond the ends of said tube and secured to one of said shells at opposite sides of said baffie.

3. A mufiler including shells arranged one within the other and spaced apart, a transverse annular baille extending between said shells andhaving an aperture, and a sheet metal member having a portion thereof in the form of a tube and extending through said aperture, longitudinal edges thereof forming a joint extending lengthwise of said tube, and projections extending beyond each of the ends of the tube from said longitudinal edges and secured to an adjacent part of the mufller, whereby said tube is held in correct relation to the muiiler and said edges are held in correct relation to each other at said joint.

4. A tuning tube for a muflier comprising a sheet of metal having a body portion in the form of a tube and having extensions of the longitudinal edge portions of the body portion, which are bent at an angle to said tube for securing to a part of a muiller.

5. A tuning tube for a muifler comprising a sheet of metal having a body portion in the form of a tube and having tabs extending beyond the ends of said body portion, said tabs being bent at an angle to the body of said tube for securing to a part of a muiller.

6. A mufiler having a pair of shells and a baflle forming resonator chambers separated from each other by said bafiie, said baffle having an aperture, a sound conducting tube extendingthrough said aperture and comprising a metal sheet having a body portion of tubular. form and having extensions projecting from the ends of said tubular body portion and secured to a shell of said mufller.

7. A mufiler having a pair of shells and a bafiie forming a pair of resonator chambers separated by said baflie, said bafiie having an aperture, a sound conducting tube comprising a metal sheet having a body portion of tubular form and extending through said aperture, the longitudinal edges of said sheet forming a longitudinal joint of said tube, and tabs extending lengthwise beyond each longitudinal edge portion of said sheet and beyond the ends of said tube and extending at an angle to said tube, and means for securing the ends of said tabs to a shell of said muffier for holding said tube in correct position on said muiller and for holding said longitudinal edges in correct relation to each other at said joint.

ROY J. MACKENZIE. LUCIEN L. HAAS. 

